Chakraborty R, Serdy J, West B, Stuckelberger M, Lai B, Maser J, Bertoni M I, Culpepper M L, Buonassisi T
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287, USA.
Rev Sci Instrum. 2015 Nov;86(11):113705. doi: 10.1063/1.4935807.
In situ characterization of micro- and nanoscale defects in polycrystalline thin-film materials is required to elucidate the physics governing defect formation and evolution during photovoltaic device fabrication and operation. X-ray fluorescence spectromicroscopy is particularly well-suited to study defects in compound semiconductors, as it has a large information depth appropriate to study thick and complex materials, is sensitive to trace amounts of atomic species, and provides quantitative elemental information, non-destructively. Current in situ methods using this technique typically require extensive sample preparation. In this work, we design and build an in situ temperature stage to study defect kinetics in thin-film solar cells under actual processing conditions, requiring minimal sample preparation. Careful selection of construction materials also enables controlled non-oxidizing atmospheres inside the sample chamber such as H2Se and H2S. Temperature ramp rates of up to 300 °C/min are achieved, with a maximum sample temperature of 600 °C. As a case study, we use the stage for synchrotron X-ray fluorescence spectromicroscopy of CuIn(x)Ga(1-x)Se2 (CIGS) thin-films and demonstrate predictable sample thermal drift for temperatures 25-400 °C, allowing features on the order of the resolution of the measurement technique (125 nm) to be tracked while heating. The stage enables previously unattainable in situ studies of nanoscale defect kinetics under industrially relevant processing conditions, allowing a deeper understanding of the relationship between material processing parameters, materials properties, and device performance.
为了阐明在光伏器件制造和运行过程中缺陷形成和演变的物理机制，需要对多晶薄膜材料中的微米和纳米级缺陷进行原位表征。X射线荧光光谱显微镜特别适合研究化合物半导体中的缺陷，因为它具有适合研究厚且复杂材料的较大信息深度，对痕量原子种类敏感，并能无损地提供定量元素信息。目前使用该技术的原位方法通常需要大量的样品制备。在这项工作中，我们设计并构建了一个原位温度台，用于在实际加工条件下研究薄膜太阳能电池中的缺陷动力学，所需的样品制备极少。仔细选择建筑材料还能在样品室内实现可控的非氧化气氛，如H2Se和H2S。实现了高达300 °C/min的升温速率，样品最高温度为600 °C。作为一个案例研究，我们将该温度台用于CuIn(x)Ga(1-x)Se2（CIGS）薄膜的同步加速器X射线荧光光谱显微镜研究，并证明了在25-400 °C温度下可预测的样品热漂移，从而在加热时能够跟踪测量技术分辨率（125 nm）量级的特征。该温度台能够在工业相关加工条件下进行以前无法实现的纳米级缺陷动力学原位研究，从而更深入地了解材料加工参数、材料性能和器件性能之间的关系。
